The use of digital image-forming apparatuses such as, for example, thermal ink-jet printers, large-format plotters, piezo-electric printers, large form plotters, laser printers, silver halide grade photo imaging apparatuses, and others has grown in recent years. The growth may be attributed to substantial improvements in print resolution and overall print quality coupled with appreciable reduction in cost, and ease of use. Today's image-forming apparatuses offer acceptable print quality for many commercial, business and household applications at costs lower than those offered in the past.
Perceived color quality can be characterized using any one of several color space systems, such as CIELAB or Munsell, as is well known in the art. With respect to Munsell color space, a given color is defined using three terms, namely Hue, Value, and Chroma. With respect to CIELAB color space, a color is defined using three terms L*, a*, and b*. With this system, L* defines the lightness of a color, and it ranges from 0 to 100 (with 100 being white). Additionally, the terms a* and b*, together, define the hue, where a* ranges from a negative number (green) to a positive number (red), and b* ranges from a negative number (blue) to a positive number (yellow). Additional terms such as h.degree. (hue angle) and C*(chroma) are used to further describe a given color, as is known to those skilled in the art.
In general, a successful ink for color ink-jet printing must have the following properties: good crusting resistance, good stability, the proper viscosity, the proper surface tension, good color-to-color bleed alleviation, rapid dry time, no negative reaction with the vehicle, consumer-safety, and low strike-through. When placed into a thermal ink-jet system, the ink set must also be kogation-resistant. However, a single ink-jet colorant and/or ink, which has good chroma, gamut, hue angle, and environmental robustness (e.g., air-fastness, light-fastness, water-fastness) is not always optimal for use with other colorants and/or ingredients of that ink, or other inks with which it is used in combination. In other words, not only does an individual colorant and/or ink (e.g., cyan, magenta, or yellow ink), have to independently have acceptable color qualities, but it should also work well when used as part of a dye and/or ink set.
Accordingly, it would be desirable to provide colorant and inks for use in ink jet printing, which when used individually as well as synergistically and in combination with other dyes and inks, have improved print quality, reliability performance, and environmental robustness.